A number of aircraft icing threat identification algorithms based on modeled conditions, as opposed to observed measurements are known. See, e.g., (1) Air Weather Service, 1980: Forecaster's Guide on Aircraft Icing. Air Weather Service (MAC) Tech. Rep. AWS/TR-80/001, Scott AFB, IL, 55 pp; (2) Appleman, H., 1954: Design of a cloud-phase chart. Bull. Amer. Meteor. Soc., 35, 223-225; (3) Bernstein, B. C., F. McDonough, M. K. Politovich, B. G. Brown, T. P. Ratvasky, D. R. Miller, C. A. Wolff, and G. Cunning, 2005: Current icing potential: Algorithm description and comparison with aircraft observations. Journal of Applied Meteorology, 44, 969-986; (4) Bernstein, B. C., C. A. Wolff, and F. McDonough, 2007: An Inferred Climatology of Icing Conditions Aloft, Including Supercooled Large Drops. Part I: Canada and the Continental United States. Journal of Applied Meteorology and Climatology, 46, 1857-1878, doi:10.1175/2007JAMC1607.1; (5) Brown, B. G. et al., 1997: Intercomparison of In-Flight Icing Algorithms. Part II: Statistical Verification Results, Weather and Forecasting, Vol. 12, American Meteorological Society, 890-914 (Brown 1997); (6) Bruintjes, R. T., B. G. Brown, J. Coen, G. Thompson, and T. L. Kane, 2003: Final report on development of icing potential product, NCAR/RAP Report to Phillips Laboratory. 190 pp (Brown 2003); (7) Dennstaedt, S. C., 2006: The Appleman Line. IFR Magazine, Vol. 22, Iss. 2, pp. 6-8, 23; (8) Politovich, M. K., and T. A. Bernstein, 2002: Aircraft icing conditions in northeast Colorado. Journal of Applied Meteorology, 41, 118-132; (9) Schultz, P., and M. K. Politovich, 1992: Toward the Improvement of Aircraft-Icing Forecasts for the Continental United States. Weather and Forecasting, 7, 491-500, doi:10.1175/1520-0434(1992)007<0491:TTIOAI>2.0.CO;2.; (10) Gregory Thompson, Roelof T. Bruintjes, Barbara G. Brown, and Frank Hage, 1997: Intercomparison of In-Flight Icing Algorithms. Part I: WISP94 Real-Time Icing Prediction and Evaluation Program. Wea. Forecasting, 12, 878-889; and (11) Tremblay, A., S. G. Cober, A. Glazer, G. Isaac, and J. Mailhot, 1996: An intercomparison of mesoscale forecasts of aircraft icing using SSM/I retrievals, Weather and forecasting, 11, 66-77. Each of those references is incorporated herein by reference.).